Insect control by insect growth regulators broadcast by volatilization

ABSTRACT

Insect control through the use of an insect growth regulators is achieved by volatilization of the active compound from a point source in a spatial region such as a room, to diffuse through the air in the region toward objects in the region such as a carpet or a piece of furniture. The ability of the insect growth regulator to retain its activity when applied in this manner, even after periods of time in excess of one month following volatilization, is surprising in view of pre-existing methods of application that involved application of the insect growth regulator directly to the surface or object of interest in liquid form.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention lies in the field of insect growth regulators andmethods of application for the control of insects.

[0003] 2. Description of the Prior Art

[0004] Insect growth regulators (including juvenile hormones) are wellknown for their use and efficacy in controlling or eliminating insectinfestation in humans, in animals, and in both residential andindustrial environments. Many types of insects are controllable byinsect growth regulators, including fleas, flour beetles, cigarettebeetles, and cockroaches. The regulators vary widely in chemicalcomposition, and two of the more prominent classes are are 2,4-dienoicacids and phenoxyphenoxy compounds, particularlyphenoxyphenoxyalkoxyheterocyclics, as well as benzoylureas and triazinederivatives. Examples of 2,4-dienoic acids and related compounds aremethoprene, hydroprene, neotenin, and epiphenonane. Examples ofphenoxyphenoxy compounds are fenoxycarb and pyriproxyfen. Examples ofbenzoylureas are lufenuron, diflubenzuron, terflubenzuron, triflumaron,hexaflumaron, and flucycloxuron. An example of a triazine derivative is2-cyclopropylamino-4,6-bis(dimethylamino)-s-triazine.

[0005] Insect growth regulators are typically applied in liquid form,either as emulsifiable concentrates that are diluted and then sprayed,or as aerosols. The propellants and solvents that are needed tofacilitate these methods of application, however, are increasinglysubject to regulatory control, and in many cases this has resulted in areduction in the performance and the aesthetics of the use of thesematerials.

SUMMARY OF THE INVENTION

[0006] It has now been discovered that insect growth regulators can beapplied in a volatilized form to diffuse through air to regions wherepotential insect infestation exists, and still achieve effective resultsin insect control. In particular, it has been discovered that a liquidformulation of an insect growth regulator when heated by simple means,such as by being placed on the surface of or in close proximity to anincandescent light bulb or by conventional heating elements of variouskinds, will generate a volatilized form of the insect growth regulatorthat will broadcast itself through a room or other spatial region toeffectively condition the region to prevent or at least substantiallyreduce the maturation of insects from pre-adult stages. Once treated inthis manner, insect control will be maintained in the room for anextended period of time. Objects in the room such as carpets, draperies,upholstered furniture, cushions and the like will no longer be activesites for insect growth, even though they may be several feet removedfrom the volatilization source or at the opposite side of the room.

[0007] These and other objects, advantages, features and embodiments ofthe invention will be more readily apparent from the descriptions below.

DETAILED DESCRIPTION OF THE INVENTION AND SPECIFIC EMBODIMENTS

[0008] One class of compounds that can be volatilized for effectivebroadcast application in accordance with this invention are 2,4-dienoicacids, including salts and esters of the acids, having the formula

[0009] in which:

[0010] R¹ is C₁-C₆ alkyl;

[0011] R² is either H, methyl, or ethyl;

[0012] R³ is either H or methyl;

[0013] R⁴ is either methyl or ethyl;

[0014] R⁵ is either H or methyl;

[0015] R⁶ is either H or methyl;

[0016] R⁷ is either methyl or ethyl;

[0017] R⁸ is either H, C₁-C₆ alkyl, C₃-C₆ alkenyl, C₃-C₆ alkynyl, C₃-C₈cycloalkyl, phenyl, naphthyl, C₇-C₁₂ aralkenyl, or a cation of lithium,sodium, potassium, calcium, strontium, copper, manganese, or zinc;

[0018] X is either Br, Cl, Fl, or OR⁹, in which R⁹ is either H, C₁-C₆alkyl or C₁-C₆ alkanoyl;

[0019] m is either zero, 1, 2, or 3; and

[0020] n is either zero, 1, 2, or 3.

[0021] In this specification and the appended claims, the term“cycloalkyl” refers to a saturated hydrocarbon ring, including ringswith one or more alkyl groups branching off from a ring carbon. Examplesare cyclopropyl, cyclopentyl, cyclohexyl, methylcyclohexyl, andcyclohexylmethyl. Preferred cycloalkyl groups are C₃-C₆ cycloalkyl, withcyclopentyl and cyclohexyl particularly preferred. The term “aralkyl”refers to an alkyl group substituted with an aromatic group both withand without one or more additional alkyl groups branching off from aring carbon. Examples of aralkyl groups are benzyl, phenylethyl,naphthylmethyl, and ethylbenzyl. Preferred aralkyl groups are C₇-C₉aralkyl, with benzyl and phenylethyl particularly preferred. The term“alkanoyl” refers to an alkyl group bonded to a carboxy group. Examplesare acetyl, propionyl, butyryl, and hexanoyl. Preferred alkanoyl groupsare C₁-C₃ alkanoyl, with acetyl and propionyl particularly preferred.

[0022] Within the scope of the above formula for 2,4-dienoic acids,salts and esters, certain groups of compounds of preferred. One suchgroup is that in which the double bonds are in an E,E or Z,Econfiguration, preferably an E,E configuration. Another group that inwhich: R¹ is methyl or ethyl; R² is methyl or ethyl; R⁷ is methyl; R⁸ isC₁-C₆ alkyl or C₃-C₆ alkynyl; X is chloro or R⁹; m is zero or 1; and nis 1; all other variables as defined above. A third group is that inwhich: R¹ is methyl or ethyl; R² is methyl; R³ is H; R⁴ is methyl; R⁵ isH; R⁶ is H; R⁷ is methyl; R⁸ is C₁-C₄ alkyl or C₃-C₄ alkynyl; X ischloro or R⁹; m is 1; and n is 1; all other variables as defined above.A fourth group is the same as the third, except that R⁹ is H, methyl,ethyl, isopropyl, t-butyl, or acetyl. A fifth group is also the same asthe third, except that R⁹ is methyl, ethyl, isopropyl, or t-butyl.Specific examples of known compounds within the scope of this formulaare 11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate, isopropyl ester(known by the generic name methoprene, and preferably the isomertrans(2), trans(4)-isopropyl11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate, or (E,E)-(7S)-11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate, isopropyl ester, knownas S-methoprene); 3,7,11-trimethyldodeca-2,4-dienoate, ethyl ester(known by the generic name hydroprene, and preferably the isomer(E,E)-(7S)-3,7,11-trimethyldodeca-2,4-dienoate, ethyl ester, known asS-hydroprene); and 2-propynyl (E,E)-3,7,11-trimethyldodeca-2,4-dienoate(known by the generic name kinoprene). Methoprene and particularly(S)-methoprene are of particular interest. In the case of hydroprene,the preferred optical configurations are (R,S) and (S), while forkinoprene the preferred configuration is (S).

[0023] Another class of compounds that can be volatilized for effectivebroadcast application in accordance with this invention are2-pyridyloxy-(lower alkylene)oxy-phenoxy compounds of the formula

[0024] in which:

[0025] R¹¹ is either an oxygen atom, a sulfur atom, or a methylenegroup;

[0026] R¹² is either a hydrogen atom or a methyl group;

[0027] R¹³ is either a hydrogen atom or a methyl group;

[0028] R¹⁴ is either an oxygen atom, a sulfur atom, or a methylenegroup;

[0029] R¹⁵ is either an oxygen atom, a sulfur atom, or a methylenegroup;

[0030] R¹⁶ is either a hydrogen atom or a fluorine atom; and

[0031] R¹⁷ is either a hydrogen atom or a fluorine atom.

[0032] Within this formula as well, certain groups of compounds arepreferred. In one such group, R¹¹, R¹⁴, and R¹⁵ are either oxygen orsulfur atoms, and preferably all are oxygen atoms. In another group, R¹⁶and R¹⁷ are both hydrogen atoms. A specific example of an insect growthregulator within the scope of this formula is 2-pyridyloxy-(loweralkylene)oxyphenoxy compound is 2-{1-methyl-2-(4-phenoxyphenoxy)-ethoxy}pyridine (known by the generic name pyriproxifen).

[0033] In the practice of this invention, the insect growth regulator isvolatilized from a liquid form such as a solution, an emulsion, or theundiluted active compound itself. Liquid solutions are particularlyconvenient, since a properly selected solvent can facilitate theabsorption of the active ingredient by a solid absorbent matrix. Thematrix may for example be a filter pad or a piece of fabric, or any suchmaterial that is readily wetted with the solution. Any solvent can beused that is not itself objectionable when volatilized, either foraesthetic reasons or for physiological reasons such as allergicreactions, carcinogenic effects, or toxicity to humans or animals.Examples of suitable solvents are volatile alcohols, water,alcohol/water mixtures, and organic solvents in general. With someactive ingredients, particularly 2,4-dienoic acids, the inclusion of anantioxidant in the solution may be beneficial. Examples of antioxidantsare butylated hydroanisole (BHA) and butylated hydroxytoluene (BHT).Insect growth regulators that are liquids at ambient temperature canalso be used without solvents.

[0034] The absorbent matrix thus wetted can be placed directly on aheating surface, such as an incandescent light bulb, or a conventionalheating device of any description that provides controlled heating. Oncevolatilized, the insect growth regulator will be effective in preventingthe maturation of insects in a spatial region surrounding the heatingelement. The spatial region may be an enclosed room or a partially orfully open space. The size of the spatial region is not critical, andthe volume in which insect control is achieved in this manner will varyto some extent with the amount of the insect growth regulator that isvolatilized, the temperature of the heating element and possibly theambient conditions of the room, as well as the choice of particularinsect growth regulator itself. In most cases, the typical spatialregion will have a volume ranging from about 10 cubic meters to about1,000 cubic meters, preferably from about 10 cubic meters to about 500cubic meters, and most preferably from about 15 cubic meters to about150 cubic meters. The surface temperature of the heating element mayalso vary, and the choice of the optimum temperature may vary with theactive ingredient. In most cases, typical volatilization temperatureswill range from about 50° C. to about 150° C., and preferably from about80° C. to about 125° C.

[0035] One of the advantages of this invention is that it can be used toprevent maturation of insects over an extended period of time in variousobjects in a spatial region in which insect eggs might reside. Objectsin the spatial region will retain their ability to prevent insectmaturation for extended periods of time, such as a month or more, aftertheir exposure to the volatilized insect growth regulator.

[0036] The following examples are offered for illustration only and arenot intended to limit to the scope of the invention.

EXAMPLE 1

[0037] This example illustrates the efficacy of S-methoprene volatilizedby heating from an incandescent light bulb in the control of fleas(Ctenocephalides felis).

[0038] Testing was performed in a test room measuring 8.5 m (28 ft.)(length)×6.1 m (20 ft) (width)×4.3 m (14 ft.) (height) with a movablepartition to reduce the room to the desired size. For this series oftests, the partition was placed in various positions such that thehorizontal area of the room was variously:

[0039] 18.6 m² (200 ft²), resulting in a room volume of 78.4 m³ (2,800ft³);

[0040] 27.9 m² (300 ft²), resulting in a room volume of 117.6 m³ (4,200ft³);

[0041] 37.2 m² (400 ft²), resulting in a room volume of 156.8 m³ (5,600ft³); and

[0042] 46.5 m² (500 ft²), resulting in a room volume of 196 m³ (7,000ft³).

[0043] A single standard 100-watt incandescent light bulb was used asthe heating source, and a felt ring that was cut to fit on the top ofthe light bulb was used as the support for the liquid S-methoprenesolution. Three liquid S-methoprene solutions were used as follows:

[0044] Solution A: S-methoprene and IRGANOX® L57 (in a weight ratio of50:1), to achieve a solution of 83.38% S-methoprene by weight. IRGANOX ®L57 (Ciba-Geigy Corp., Hawthorne, N.Y., USA) is a liquid aminicantioxidant in the form of an alkylated diphenylamine. No solvents wereused.

[0045] Solution B: S-methoprene and BHT (in a weight ratio of 50:1),dissolved in a mixture of 1-methoxy-2-propanol and deionized water (in aweight ratio of 84:16) to achieve a solution of 5.2% S-methoprene byweight.

[0046] Solution C: S-methoprene and BHT (in a weight ratio of 50:1),dissolved in a mixture of 1-methoxy-2-propanol and Belmay B-5 Fragrance(in a weight ratio of 44:56) to achieve a solution of 5% S-methoprene byweight.

[0047] As the infested target, circular pieces of carpet were used. Eachpiece was 7.6 cm (3 inches) in diameter cut from a 1.3-cm (0.5-inch)pile nylon carpet, and individual circles were placed at distances of0.61 m (2 ft), 3.0 m (10 ft), and 6.1 m (20 ft) from the light bulb.

[0048] The felt ring in each experiment was wetted with 2 g of solution.In the case of Solution A, this resulted in 1.8 g of S-methoprene beingapplied to the felt ring. In the case of Solutions B and C, thisresulted in 0.1 g of S-methoprene being applied to the felt ring. Thebulb was turned on for periods of time ranging from 4 h to 120 h. Thisis referred to below as the “Activation Time.” The temperature of thebulb surface at the location of the felt ring was approximately 215° F.(102° C.). In some of the tests, a horizontal barrier was placed abovethe carpet circles at distances of 5.1 cm (2 inches) or 7.6 cm (3inches), to simulate penetration of the S-methoprene todifficult-to-reach places such as under furniture. The carpet circleswere placed in two positions below the barrier—one in which the centerof the carpet circle was 30 cm (12 inches) from the edge of the barrier(identified below as “Position 1”), and the other in which the center ofthe carpet circle was 7.6 cm (3 inches) from the edge of the barrier(identified below as “Position 2”).

[0049] After these exposures, the carpet circles were removed from theroom, and sprinkled with flea rearing media and infested with 100 viableflea eggs. Similar carpet circles that had not undergone exposure to thevolatilized S-methoprene were similarly sprinkled and infested. Theexposed (test) and unexposed (control) carpet circles were then placedin a warm (27° C., 80° F.), high humidity (80% relative humidity) roomfor 35 days to allow any viable flea eggs in the circles to develop toadult fleas. In some of the tests, the carpet circles were allowed torest for 35 days after removal from the treatment room before beinginfested with the flea eggs, to test for residual efficacy. In allcases, efficacy was determined by comparing the results from testcircles to those from the control circles. The results are listed inTable I. TABLE I Test Results Using Methoprene Volatilized by Light BulbAmount of Acti- S-Methoprene Room vation Efficacy at IndicatedVolatilized Size Time Distance from Source (g) (m³) (h) 0.61 m 3.0 m 6.1m 1.8 78.4 120 100% 100% 100% 0.1 78.4 24  99%  99%  99% 35-Day ResidualEffect: 0.1 78.4 24  96%  96%  97% 0.1 78.4 4 Under 2-in. OverheadBarrier: Position 1: 99% Position 2: 96% 0.1 78.4 4 Under 3-in. OverheadBarrier: Position 1: 100% Position 2: 100% 0.1 117.6 4 100% 99.4% 99.4%0.1 186.8 4 100% 99.6% 100% 0.1 196 4  95% 97.3% 96.5%

[0050] These results show that excellent control was achieved in allcases, including exposures at the lower dosage rate, the residual effect35 days after the exposure, and exposures obstructed by an overheadbarrier.

EXAMPLE 2

[0051] This example is a further illustration of the efficacy ofS-methoprene volatilized by heating from an incandescent light bulb inthe control of fleas. The test was performed in a conventionalresidential living room with a floor area of 21.5 m² (231 ft²). A singlestandard 60-watt incandescent bulb was used as the heat source, with afelt ring containing 0.1 g of S-methoprene (using Solution B of Example1). The temperature of the bulb surface at the location of the felt ringwas approximately 200° F. (93° C.). The exposure time (the length oftime that the lamp containing the bulb was turned on) was four hours.The carpet circles were placed twenty feet (6.1 m) from the bulb.

[0052] After exposure to the volatilized S-methoprene, the carpetcircles were each aged (allowed to rest without additional exposure) for1, 2, 3, or 4 months. They were then challenged by infestation with fleaeggs in the same manner as described above in Example 1. The results,expressed in terms of the number of adult fleas emerging after 35 days,are listed in Table II, together with corresponding results from controlsamples. TABLE II Further Test Results Using Methoprene Volatilized byLight Bulb Months Number of Adult Fleas After Emerging From 100 EggsSample Treatment→ 1 2 3 4 Test Samples: 1 2 6 16 4 2 3 5 1 1 3 3 2 0 8 42 0 0 4 5 5 2 0 1 6 2 4 5 6 Mean→ 2.8/2.7 3.2/1.9 3.7/0.7 4.0/3.0(Arithmetic/ Geometric) Control Samples: 1 53 65 54 78 2 63 73 67 60 365 66 62 82 4 58 77 62 61 5 71 64 59 75 6 73 73 61 65 Mean→ 63.8/63.469.7/69.5 60.8/60.7 70.2/69.6 (Arithmetic/ Geometric) Percent→ 95.6/95.895.5/97.3 94.0/98.9 94.3/95.7 Control (Arithmetic/ Geometric)

[0053] These results show that excellent control was achieved in allcases, and that the treatment is persistent for up to four months.

EXAMPLE 3

[0054] This example illustrates the efficacy of S-methoprene volatilizedby a plug-in heater designed for use with mosquito repellents. Theheater was an AgRevo heater, 110-120v, 50-60 Hz, 5 watts, purchased fromDBK Espana Household Technologies, and the tests were performed in thesame test room used for Example 1, adjusted to a floor area of 18.6 m²(200 ft²), resulting in a room volume of 78.4 m³ (2,800 ft³). TheS-methoprene was placed in the heater by wetting a Whatman filter padconsisting of 50% cellulose and 50% glass fiber, the wetting solutionconsisting of 8.8% (by weight) S-methoprene in neat 1-methoxy2-propanol. The amount of solution used was 1.2 g, resulting in 0.1 g ofS-methoprene in the pad. Carpet circles were used as in the precedingexamples, and all other procedures were the same as those in Example 1.Carpet circles were placed at distances of 0.61 m (2 ft), 3.0 m (10 ft),and 6.1 m (20 ft) from the plug-in-heater, with three carpet circles ateach location. Three additional carpet circles were retained outside theroom to avoid exposure to the volatilized S-methoprene for use ascontrols. The activation time for the test circles was four hours.Efficacy was determined by comparing the results from the test circlesto those from the control circles. The results are listed in Table III.TABLE III Test Results Using Methoprene Volatilized by Plug-In StyleInsecticide Heater Adult Flea Emergence Distance From (From 100 Eggs) %Efficacy Heater (m) Individual Tests Average (Relative to Control)(control) 13/14/14 13.7 0.61 0/1/2 1 92.7 3.0  1/0/0 0.3 97.8 6.1  1/0/00.3 97.8 Overall: 96.1

[0055] These results indicate excellent control at all distances fromthe plug-in heater and are very close to those obtained with theincandescent light bulb as the volatilization medium.

[0056] The foregoing is offered primarily for purposes of illustration.It will be readily apparent to those skilled in the art that thequantities, compositions, methods of volatilization, equipment, andother parameters described herein may be further modified or substitutedin various ways without departing from the spirit and scope of theinvention.

What is claimed is:
 1. A method for controlling insect infestation on anobject residing in an air-containing spatial region, said methodcomprising heating an insect growth regulator in liquid form tovolatilize said insect growth regulator whereby said insect growthregulator so volatilized diffuses through air in said region to saidobject in an amount sufficient to prevent the maturation of insectstherein from pre-adult stages of growth.
 2. A method in accordance withclaim 1 in which said insect growth regulator is a member selected fromthe group consisting of 2-pyridyloxy-(lower alkylene)oxyphenoxycompounds and 2,4-dienoic acids.
 3. A method in accordance with claim 1in which said insect growth regulator is a 2,4-dienoic acid.
 4. A methodin accordance with claim 1 in which a plurality of such objects residein said air-containing spatial region, said air-containing spatialregion is from about 10 cubic meters to about 1000 cubic meters, andsaid method comprises controlling insect infestation in all of saidplurality of objects.
 5. A method in accordance with claim 1 in which aplurality of such objects reside in said air-containing spatial region,said air-containing spatial region is from about 10 cubic meters toabout 500 cubic meters, and said method comprises controlling insectinfestation in all of said plurality of objects.
 6. A method inaccordance with claim 1 in which a plurality of such objects reside insaid air-containing spatial region, said air-containing spatial regionis from about 15 cubic meters to about 150 cubic meters, and said methodcomprises controlling insect infestation in all of said plurality ofobjects.
 7. A method in accordance with claim 1 in which said insectgrowth regulator is a 2,4-dienoic acid having the formula

in which: R¹ is C₁-C₆ alkyl; R² is a member selected from the groupconsisting of H, methyl, and ethyl; R³ is a member selected from thegroup consisting of H and methyl; R⁴ is a member selected from the groupconsisting of methyl and ethyl; R⁵ is a member selected from the groupconsisting of H and methyl; R⁶ is a member selected from the groupconsisting of H and methyl; R⁷ is a member selected from the groupconsisting of methyl and ethyl; R⁸ is a member selected from the groupconsisting of H, C₁-C₆ alkyl, C₃-C₆ alkenyl, C₃-C₆ alkynyl, C₃-C₈cycloalkyl, phenyl, naphthyl, C₇-C₁₂ aralkenyl, and cations of metalsselected from the group consisting of lithium, sodium, potassium,calcium, strontium, copper, manganese, and zinc; X is a member selectedfrom the group consisting of Br, Cl, Fl, and OR⁹, in which R⁹ is amember selected from the group consisting of H, C₁-C₆ alkyl and C₁-C₆alkanoyl; m is zero, 1, 2, or 3; and n is zero, 1,2,or
 3. 8. A method inaccordance with claim 7 in which: R¹ is a member selected from the groupconsisting of methyl and ethyl; R² is a member selected from the groupconsisting of methyl, and ethyl; R⁷ is methyl; R⁸ is a member selectedfrom the group consisting of C₁-C₆ alkyl and C₃-C₆ alkynyl; X is amember selected from the group consisting of Cl and OR⁹; m is zero or 1;and n is
 1. 9. A method in accordance with claim 8 in which said2,4-dienoic acid is 11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate,isopropyl ester.
 10. A method in accordance with claim 8 in which said2,4-dienoic acid is(E,E)-(7S)-11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate, isopropylester.
 11. A method in accordance with claim 8 in which said 2,4-dienoicacid is 3,7,11-trimethyldodeca-2,4-dienoate, ethyl ester.
 12. A methodin accordance with claim 8 in which said 2,4-dienoic acid is(E,E)-(7S)-3,7,11-trimethyldodeca-2,4-dienoate, ethyl ester.
 13. Amethod in accordance with claim 1 in which said insect growth regulatoris a 2-pyridyloxy-(lower alkylene)oxyphenoxy compound having theformula:

in which: R¹¹ is a member selected from the group consisting of anoxygen atom, a sulfur atom, and a methylene group; R¹² is a memberselected from the group consisting of a hydrogen atom and a methylgroup; R¹³ is a member selected from the group consisting of a hydrogenatom and a methyl group; R¹⁴ is a member selected from the groupconsisting of an oxygen atom, a sulfur atom, and a methylene group; R¹⁵is a member selected from the group consisting of an oxygen atom, asulfur atom, and a methylene group; R¹⁶ is a member selected from thegroup consisting of a hydrogen atom and a fluorine atom; and R¹⁷ is amember selected from the group consisting of a hydrogen atom and afluorine atom.
 14. A method in accordance with claim 13 in which R¹¹,R¹⁴ and R¹⁵ are oxygen atoms, and R¹⁶ and R¹⁷ are hydrogen atoms.
 15. Amethod in accordance with claim 13 in which said 2-pyridyloxy-(loweralkylene)oxyphenoxy compound is2-{1-methyl-2-(4-phenoxyphenoxy)-ethoxy}pyridine.
 16. A method inaccordance with claim 1 in which said method comprises contacting saidinsect growth regulator in liquid form with a heated surface, saidsurface being at a temperature of from about 50° C. to about 150° C. 17.A method in accordance with claim 16 in which said heated surface is theexternal surface of an incandescent light bulb.
 18. A method inaccordance with claim 16 in which said heated surface is the surface ofan electrically heated heating element.
 19. A method in accordance withclaim 1 in which said insect growth regulator is isopropyl(E,E)-(7S)-11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate and saidmethod comprises contacting said insect growth regulator in liquid formwith a heated surface, said surface being at a temperature of from about80° C. to about 125° C.
 20. A method in accordance with claim 1 in whichsaid liquid form is a liquid solution of said insect growth regulatorand an antioxidant.
 21. A method in accordance with claim 1 in whichsaid insect growth regulator is isopropyl(E,E)-(7S)-11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate and saidliquid form is a liquid solution of said insect growth regulator and anantioxidant selected from the group consisting of butylatedhydroxyanisole and butylated hydroxytoluene in an organic solvent.
 22. Amethod in accordance with claim 1 in which said insect growth regulatoris isopropyl (E,E)-(7S)- 11-methoxy-3,7,11-trimethyldodeca-2,4-dienoateand said liquid form is a liquid solution of said insect growthregulator and an antioxidant selected from the group consisting ofbutylated hydroxyanisole and butylated hydroxytoluene in a solventcomprising a member selected from the group consisting of a volatilealcohol, water, and a mixture of a volatile alcohol and water.
 23. Amethod in accordance with claim 16 in which said method comprisescontacting a solid absorbent support matrix wetted with said insectgrowth regulator in liquid form with said heated surface.